JP2004088865A - Power conversion apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a small-sized low-cost power converter capable of detecting the melting of fuses without using mechanical contacts. <P>SOLUTION: The power converter is provided with a diode rectification circuit 3 connected with three-phase AC power supplies 1U, 1V, 1W through the input fuses 2U, 2V, 2W, a smoothing capacitor 4 connected with a DC output part of the diode rectification circuit, a DC voltage detection circuit 7 for detecting the voltage of a DC output part in the diode rectification circuit, and a means for determining the operating states of the fuses 2U, 2V, 2W with the output of the DC voltage detection circuit 7. The means determines the operating states of the fuses 2U, 2V, 2W by whether or not the output of the DC voltage detection circuit 7 after power ON reaches a predetermined level or higher in a prescribed time. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a power converter that obtains DC power using one or a plurality of three-phase diode rectifiers.
[0002]
[Prior art]
When obtaining a DC voltage from an AC power supply, a diode rectifier is widely used. Diode rectifiers are used in a wide variety of applications because they have a simple circuit configuration and can easily obtain a DC voltage.
[0003]
Conventionally, in a diode rectifier, a protection circuit such as a fast-blow fuse is inserted at each input of the diode rectifier so that when a short-circuit fault of the diode or a DC short-circuit fault occurs, damage to the short-circuit of the power supply does not spread. In general, a mechanical contact switch is used to detect the fusing of these fast-blow fuses, and the output of each contact is fed back to the control system circuit.
[0004]
FIG. 18 is a configuration diagram of a conventional power conversion device having an AC input fuse blown detection circuit of a three-phase diode rectifier. Power is supplied from the three-phase AC power supplies 1U, 1V, and 1W to the three-phase diode converter 3 via the fuses 2U, 2V, and 2W, respectively. The DC power output from the three-phase diode converter 3 is stored in the smoothing capacitor 4. Each of the fuses 2U, 2V, 2W has a fuse blow detection contact 5U, 5V, 5W for blow detection, and this contact signal is input to the control circuit 6, and when one of the fuses blows, the device is immediately stopped.
[0005]
[Problems to be solved by the invention]
However, the input fuse blown detection circuit of the diode rectifier thus configured requires a mechanical contact switch for each fuse, and it is necessary to insulate each of the circuits. For this reason, there are problems such as an increase in the outer shape and an increase in wiring cost.
[0006]
Therefore, an object of the present invention is to provide a small-sized, low-cost power conversion device capable of detecting the fusing of a fuse without using a mechanical contact.
[0007]
[Means for Solving the Problems]
To achieve the above object, a power converter of the present invention includes a three-phase AC power supply, a diode rectifier circuit connected via an input fuse, and a smoothing capacitor connected to a DC output part of the diode rectifier circuit. A DC voltage detection circuit for detecting a voltage of a DC output unit of the diode rectifier circuit; and a unit for determining an operation state of the fuse based on an output of the DC voltage detection circuit, wherein the unit is provided after power-on. An operation state of the fuse is determined based on whether an output of the DC voltage detection circuit has reached a predetermined level or more within a predetermined time.
[0008]
To achieve the above object, a power converter of the present invention includes a three-phase AC power supply, a diode rectifier circuit connected via an input fuse, and a smoothing capacitor connected to a DC output part of the diode rectifier circuit. A DC voltage detection circuit for detecting a voltage of a DC output portion of the diode rectifier circuit; and a unit for determining an operation state of the fuse based on an output of the DC voltage detection circuit, wherein the unit includes the DC voltage detection circuit. The operation state of the fuse is determined based on whether or not the ripple frequency included in the output is below a predetermined value.
[0009]
To achieve the above object, a power converter of the present invention includes a three-phase AC power supply, a diode rectifier circuit connected via an input fuse, and a smoothing capacitor connected to a DC output part of the diode rectifier circuit. A DC current detector for detecting a current of a DC output portion of the diode rectifier circuit; and a unit for determining an operation state of the fuse based on an output of the DC current detector, wherein the unit is provided after power-on. An operation state of the fuse is determined based on whether an output of the DC current detector has reached a predetermined level or less within a predetermined time.
[0010]
To achieve the above object, a power converter of the present invention includes a three-phase AC power supply, a diode rectifier circuit connected via an input fuse, and a smoothing capacitor connected to a DC output part of the diode rectifier circuit. A DC current detector for detecting a current of a DC output portion of the diode rectifier circuit; and a unit for determining an operation state of the fuse based on an output of the DC current detector, wherein the unit includes the DC current detector. The operation state of the fuse is determined based on whether or not the ripple frequency included in the output is below a predetermined value.
[0011]
To achieve the above object, the power converter of the present invention is a three-phase AC power supply, a diode rectifier circuit connected via an input fuse, and a smoothing capacitor connected to a DC output part of the diode rectifier circuit, An AC current detector that detects an input current of the diode rectifier circuit, and a unit that determines an operation state of the fuse based on an output of the AC current detector, wherein the unit includes an output of the AC current detector. The operation state of the fuse is determined based on whether or not the level has become lower than a predetermined level.
[0012]
In order to achieve the above object, a power converter according to the present invention includes a plurality of diode rectifier circuits connected to a three-phase AC power supply via input fuses, respectively, and the respective DC rectifier circuits of the plurality of diode rectifier circuits. A smoothing capacitor connected to the output unit, a DC voltage detection circuit for detecting a voltage of each DC output unit of the plurality of diode rectifier circuits, and an operation state of the fuse based on an output of each of the DC voltage detection circuits. Determining means for determining the operation state of each of the fuses based on whether or not a difference between respective outputs of the DC voltage detection circuit is equal to or more than a predetermined level. And
[0013]
In order to achieve the above object, a power converter according to the present invention includes a plurality of diode rectifier circuits connected to a three-phase AC power supply via input fuses, respectively, and the respective DC rectifier circuits of the plurality of diode rectifier circuits. A smoothing capacitor connected to an output unit, a DC current detector for detecting a current of each DC output unit of the plurality of diode rectifier circuits, and an operation state of the fuse based on an output of each DC current detector. Determining means for determining the operation state of each of the fuses based on whether or not the difference between the outputs of the respective DC current detectors is equal to or greater than a predetermined level. According to the present invention, it is possible to provide a small-sized, low-cost power converter capable of detecting the fusing of a fuse without using a mechanical contact.
[0014]
BEST MODE FOR CARRYING OUT THE INVENTION
(First Embodiment)
Hereinafter, a first embodiment of a power converter according to the present invention will be described with reference to FIGS. FIG. 1 is a configuration diagram of a power conversion device according to a first embodiment of the present invention.
[0015]
Power is supplied from the three-phase AC power supplies 1U, 1V, and 1W to the three-phase diode converter 3 via the fuses 2U, 2V, and 2W, respectively. The DC power output from the three-phase diode converter 3 is stored in the smoothing capacitor 4. Here, each of the fuses 2U, 2V, and 2W does not have a fuse fusing detection contact for fusing detection.
[0016]
DC voltage detection circuit 7 detects a voltage applied to smoothing capacitor 4. Upon receiving this signal, the fuse blowing determination circuit 8 determines whether the fuse is blown, and supplies the output to the control circuit 6.
[0017]
FIG. 2 is a configuration diagram showing details of the fuse blowing judgment circuit 8 of FIG. In FIG. 2, a fuse blowing determination circuit 8 includes a time setting device 9, a voltage timer output device 10 that outputs a voltage after a set time after the DC voltage starts to change from 0 voltage, this output, and a detection voltage. And a voltage comparison circuit 12 for comparing with a set voltage level from the level setter 11.
[0018]
The operation of the fuse blowing judgment circuit 8 described above will be described below.
[0019]
FIG. 3 shows the time transition of the DC voltage from when the power is turned on when all the fuses are sound and when one fuse is blown. When all the fuses are sound, three-phase full-wave rectification is achieved. The charging time for the smoothing capacitor 4 is relatively short. However, when one fuse is blown, single-phase full-wave rectification is achieved. As compared with the state of full-wave rectification, even though the peak voltage is the same, the charging is performed in a state in which the average voltage is lower, so that the charging time to the smoothing capacitor 4 becomes longer. Therefore, if the setting time of the time setting device 9 and the setting level of the detection voltage level setting device 11 are selected to appropriate values, it is possible to detect the blown fuse.
[0020]
As a method of determining the set time and the set level, there are a method of calculating from a CR time constant of a power supply and a DC unit and a power supply voltage, and a method of measuring and determining a three-phase full-wave rectified waveform when a fuse is sound. is there.
[0021]
As described above, in the first embodiment, the input fuse blow detection can be performed only by using the DC voltage detection circuit 7 and the fuse blow determination circuit 8.
[0022]
Therefore, it is possible to provide a small-sized, low-cost power conversion device capable of detecting the blowing of a fuse without using a mechanical contact.
[0023]
(Second embodiment)
FIG. 4 is a configuration diagram showing details of the fuse blowing determination circuit 8 according to the second embodiment of the present invention. Here, the overall configuration of the second embodiment of the present invention is exactly the same as the configuration diagram of the power converter according to the first embodiment of the present invention in FIG.
[0024]
In FIG. 4, the fuse blowing judgment circuit 8 includes a voltage ripple frequency detection circuit 13 for detecting the frequency of the voltage ripple, and a frequency comparison circuit 15 for comparing the frequency set by the detection frequency setting device 14.
[0025]
FIG. 5 shows DC voltage waveforms when all fuses are sound and when one fuse is blown. When all the fuses are sound, three-phase full-wave rectification occurs, and the ripple frequency of the rectifier circuit is six times the fundamental frequency. Therefore, the ripple frequency is twice the fundamental frequency. Therefore, if the set frequency to be compared with the frequency of the ripple is set to an appropriate value, it is possible to detect the blown fuse.
[0026]
The following method can be adopted as an algorithm for detecting the ripple frequency.
[0027]
Normally, the minimum value Vdc (min) of the DC voltage when all three phases are sound and performing full-wave rectification and having a maximum load on the DC side is defined as a line voltage effective value of the input AC being Vin. Then
Vdc (min) = √2 × Vin × √3 / 2
It is.
[0028]
Therefore, the DC voltage is monitored as needed, and when the DC voltage falls below the Vdc (min), the measurement of the counter is started and the count is incremented for each sampling. Then, the frequency of the voltage ripple can be detected from the difference in the count from when the voltage exceeds Vdc (min) to when the voltage falls again below Vdc (min).
[0029]
According to the above method, when all the fuses of the three phases are sound, the DC voltage does not fall below Vdc (min), so that the count value is not counted up at 0 and the frequency is infinite.
[0030]
On the other hand, even if one of the fuses is blown, if the load current is low, the blowout of the fuse cannot be detected without falling below the Vdc (min), but the operating current of the device is low because the current flowing through the AC fuse is low. And the operation can be continued.
[0031]
As described above, in the second embodiment, input fuse blowing detection can be performed only by using the DC voltage detection circuit 7 and the fuse blowing determination circuit 8. Further, even if one of the fuses is blown, the operation can be continued up to the limit of the device.
[0032]
Therefore, it is possible to provide a small-sized, low-cost power conversion device capable of detecting the blowing of a fuse without using a mechanical contact.
[0033]
(Third embodiment)
Hereinafter, a third embodiment of the power converter according to the present invention will be described with reference to FIGS. FIG. 6 is a configuration diagram of a power conversion device according to the third embodiment of the present invention. Regarding each part of the third embodiment, the same parts as those of the power converter according to the first embodiment of FIG. 1 are denoted by the same reference numerals, and description thereof is omitted. The third embodiment is different from the first embodiment in that a DC current detector 16 is used instead of the DC voltage detection circuit 7 in FIG. The configuration is different.
[0034]
FIG. 7 is a circuit diagram showing details of the fuse blowing judgment circuit 8 of FIG. In FIG. 7, the fuse blowing determination circuit 8 includes a time setting device 9, a current timer output device 17 for outputting a current after a set time from when the DC current starts to change from 0 current, and a detection current level setting device 18 And a current comparison circuit 19 that compares the current level with the set level.
[0035]
The operation of the fuse blowing judgment circuit 8 described above will be described below.
[0036]
FIG. 8 shows the time transition of the DC current from the power-on when all the fuses are sound and when one fuse is blown. When one fuse is blown, the smoothing capacitor 4 is charged with the single-phase full-wave rectified waveform shown in FIG. 5, so that the charging is performed in comparison with the charging with the three-phase full-wave rectified waveform when all the fuses are sound. Time gets longer. Therefore, if an appropriate value is selected for the set time and the set level to be compared, fuse blowing can be detected.
[0037]
As a method of determining the time and the set level, there are a method of calculating from a CR time constant of the power supply and the DC unit and the power supply voltage, and a method of measuring and determining a waveform when the fuse is sound.
[0038]
As described above, in the third embodiment, the input fuse blow detection can be performed only by using the DC current detector 16 and the fuse blow determination circuit 8.
[0039]
Therefore, it is possible to provide a small-sized, low-cost power conversion device capable of detecting the blowing of a fuse without using a mechanical contact.
[0040]
(Fourth embodiment)
FIG. 9 is a configuration diagram showing details of the fuse blowing determination circuit 8 of the power converter according to the fourth embodiment of the present invention. The overall configuration of the fourth embodiment of the present invention is exactly the same as the configuration diagram of the power converter according to the third embodiment of the present invention in FIG.
[0041]
In FIG. 9, the fuse blowing determination circuit 8 includes a current ripple frequency detection circuit 20 for detecting the frequency of the current ripple, and a frequency comparison circuit 15 for comparing the frequency set by the detection frequency setting unit 14.
[0042]
FIG. 10 shows DC current waveforms when all fuses are sound and when one fuse is blown. If all the fuses are sound, three-phase full-wave rectification occurs. Therefore, the ripple frequency of the rectifier circuit is six times the fundamental frequency. And the ripple frequency is twice the fundamental frequency. Therefore, if the set cycle to be compared with the cycle of the ripple is appropriately selected, the blown fuse can be detected.
[0043]
There are the following methods for detecting the ripple frequency.
[0044]
Normally, the maximum value of the direct current in the converter is determined by the device capacity.
[0045]
The DC current is monitored at any time, and when the current exceeds the maximum current value, the counter starts counting and counts up at each sampling. Then, the frequency of the current ripple can be detected from the difference in the counts from when the current falls below the maximum value to when the current rises again.
[0046]
According to the above method, when all three-phase fuses are sound, the DC current does not exceed the current maximum value, so that the count value is not counted up at 0 and the frequency is infinite.
[0047]
Even if one of the fuses is blown, if the load current is low, the current does not exceed the maximum current value, and it is not possible to detect the blowout of the fuse. It is within the capacity and the operation can be continued.
[0048]
As described above, in the seventh embodiment, the input fuse blow detection can be performed only by using the DC current detector 16 and the fuse blow determination circuit 8. Further, even if one of the fuses is blown, the operation can be continued up to the limit of the device.
[0049]
Therefore, it is possible to provide a small-sized, low-cost power conversion device capable of detecting the blowing of a fuse without using a mechanical contact.
[0050]
(Fifth embodiment)
Hereinafter, a fifth embodiment of the power converter according to the present invention will be described with reference to FIGS. FIG. 11 is a configuration diagram of a power conversion device according to a fifth embodiment of the present invention. Regarding each part of the fifth embodiment, the same parts as those of the power converter according to the first embodiment of FIG. 1 are denoted by the same reference numerals, and description thereof will be omitted. The fifth embodiment differs from the first embodiment in that an AC current detector 21 is used instead of the DC voltage detection circuit 7 in FIG. The AC current detector 21 is provided for one phase of the three-phase AC power supply, for example, the U phase.
[0051]
FIG. 12 is a circuit diagram showing details of the fuse blowing judgment circuit 8 of FIG. In FIG. 12, a fuse blowing determination circuit 8 includes a current comparison circuit 19a that determines whether the detected AC current value for one phase is 0, a detected AC current value for one phase, and a detected current level setting. A current comparison circuit 19b for comparing the level with the set level from the circuit 18 and an OR circuit 22.
[0052]
If the U-phase fuse 2U to which the AC current detection circuit 21 is attached is blown, the current flowing in that phase becomes 0, and the logical output of the current comparison circuit 19a becomes true. Further, if the fuse of the phase to which the AC current detection circuit is not attached is blown, a single-phase full-wave rectification state is obtained as shown in FIG. 13, and the current maximum value is smaller than the three-phase full-wave rectification state when the fuse is not blown. Becomes larger. Therefore, if the current setting level to be compared is selected to an appropriate value, the logical output of the current comparison circuit 19b at this time becomes true. By taking the logical sum of these in the logical sum circuit 22, even if the fuse of any phase has blown, the blown fuse can be detected.
[0053]
FIG. 11 shows a case where the current detector is inserted in the U phase, but the same applies to a case where the current detector is inserted in another phase. Although the case where only one phase is used is shown, the same effect is obtained when two phases are used or when two phase currents are detected by one current detector at a time. can get.
[0054]
As described above, in the fifth embodiment, the input fuse blow detection can be performed only by using at least one AC current detector 21 and the fuse blow determination circuit 8.
[0055]
Therefore, it is possible to provide a small-sized, low-cost power conversion device capable of detecting the blowing of a fuse without using a mechanical contact.
[0056]
(Sixth embodiment)
Hereinafter, a sixth embodiment of the power converter according to the present invention will be described with reference to FIGS. FIG. 14 is a configuration diagram of a power conversion device according to the sixth embodiment of the present invention. Regarding each part of the sixth embodiment, the same parts as those of the power converter according to the first embodiment of FIG. 1 are denoted by the same reference numerals, and description thereof will be omitted. This sixth embodiment differs from the first embodiment in that, in addition to the diode rectifier circuit of FIG. 1, a three-phase AC power supply 1aU, 1aV, 1aW, a fuse 2aU, 2aV, 2aW, a diode converter 3a, 1 has another diode rectifier circuit having the same configuration as the diode rectifier circuit of FIG. 1 constituted by the smoothing capacitor 4a, and the outputs of the respective voltage detection circuits 7 and 7a are input to the fuse blowing determination circuit 8. .
[0057]
FIG. 15 is a circuit diagram showing details of the fuse blowing judgment circuit 8 of FIG. In FIG. 15, the fuse blowing determination circuit 8 includes a voltage comparison circuit 12 that compares the difference between the voltages detected by the DC voltage detection circuits 7 and 7a with the voltage setting level from the voltage detection level setting unit 11, respectively. .
[0058]
As in the first embodiment, when all fuses are sound, the voltage waveform is three-phase full-wave rectified. However, when one fuse is blown, single-phase full-wave rectification is performed. When the fuse of one rectifier circuit blows, the voltage difference with the other rectifier circuit increases. Therefore, if this set level is selected to an appropriate value, fuse blowout can be detected.
[0059]
Further, when the fuse is blown, the voltage of the blown side is always reduced, so that it is possible to determine which side fuse has been blown by the difference in the magnitude of the voltage.
[0060]
FIG. 14 shows a case where each input AC power supply is independent, but the same effect can be obtained even if the power supply is common. In addition, although the case where the DC buses are independent of each other is shown, when the input AC power supply is insulated, a case where one DC bus is shared and a double DC voltage is generated may be considered. Fuse blow detection is possible.
[0061]
As described above, in the sixth embodiment, input fuse blow detection can be performed only by using the DC voltage detection circuits 7 and 7a and the fuse blow determination circuit 8.
[0062]
Therefore, it is possible to provide a small-sized, low-cost power conversion device capable of detecting the blowing of a fuse without using a mechanical contact.
[0063]
(Seventh embodiment)
Hereinafter, a seventh embodiment of the power converter according to the present invention will be described with reference to FIGS. FIG. 16 is a configuration diagram of a power conversion device according to the seventh embodiment of the present invention. Regarding each part of the seventh embodiment, the same parts as those of the power converter according to the sixth embodiment of FIG. 14 are denoted by the same reference numerals, and description thereof will be omitted. The seventh embodiment differs from the sixth embodiment in that current detectors 16 and 16a are provided instead of the voltage detection circuits 7 and 7a in FIG. It is the point that is input to.
[0064]
FIG. 17 is a circuit diagram showing details of the fuse blowing judgment circuit 8 of FIG. In FIG. 17, the fuse blowing determination circuit 8 includes a current comparison circuit 19 that compares the difference between the currents detected by the DC current detection circuits 16 and 16a with the current setting level from the detected current level setting unit 18. .
[0065]
As in the fourth embodiment, when all the fuses are sound, the current waveform is three-phase full-wave rectified. However, when one fuse is blown, single-phase full-wave rectification is performed. When the fuse of the rectifier circuit blows, the current difference from the other rectifier circuit increases. Therefore, if the current setting level is selected to be an appropriate value, fuse blowing can be detected.
[0066]
In addition, when a fuse is blown, the current on the blown side always increases, so that it is possible to determine which side fuse has blown based on the difference in the magnitude of the current.
[0067]
FIG. 16 shows a case where each input AC power supply is independent, but the same effect is obtained even if the power supply is common. In addition, although the case where the DC buses are independent of each other is shown, when the input AC power supply is insulated, it is conceivable that one of the DC buses is shared and a double DC voltage is generated. Fusing detection is possible.
[0068]
As described above, in the seventh embodiment, the blowing of the input fuse can be detected only by using the DC current detectors 16a and 16b and the fuse blowing determination circuit 8.
[0069]
Therefore, it is possible to provide a small-sized, low-cost power conversion device capable of detecting the blowing of a fuse without using a mechanical contact.
[0070]
【The invention's effect】
As described above, according to the present invention, it is possible to provide a small-sized, low-cost power conversion device capable of detecting the fusing of a fuse without using a mechanical contact.
[Brief description of the drawings]
FIG. 1 is a configuration diagram of a power converter according to first and second embodiments of the present invention.
FIG. 2 is a detailed configuration diagram of a fuse blowing determination circuit according to the first embodiment of the present invention.
FIG. 3 is an example of a rectified voltage waveform at the time of startup during three-phase full-wave rectification and single-phase full-wave rectification.
FIG. 4 is a detailed configuration diagram of a fuse blowing determination circuit according to a second embodiment of the present invention.
FIG. 5 is an example of a rectified voltage waveform at the time of load during three-phase full-wave rectification and single-phase full-wave rectification.
FIG. 6 is a configuration diagram of a power converter according to third and fourth embodiments of the present invention.
FIG. 7 is a detailed configuration diagram of a fuse blowing determination circuit according to a third embodiment of the present invention.
FIG. 8 is an example of a rectified current waveform at the time of startup during three-phase full-wave rectification and single-phase full-wave rectification.
FIG. 9 is a detailed configuration diagram of a fuse blowing determination circuit according to a fourth embodiment of the present invention.
FIG. 10 is an example of a rectified current waveform at the time of load during three-phase full-wave rectification and single-phase full-wave rectification.
FIG. 11 is a configuration diagram of a power conversion device according to a fifth embodiment of the present invention.
FIG. 12 is a detailed configuration diagram of a fuse blowing determination circuit according to a fifth embodiment of the present invention.
FIG. 13 is an example of an AC current waveform at the time of load during three-phase full-wave rectification and single-phase full-wave rectification.
FIG. 14 is a configuration diagram of a power conversion device according to a sixth embodiment of the present invention.
FIG. 15 is a detailed configuration diagram of a fuse blowing determination circuit according to a sixth embodiment of the present invention.
FIG. 16 is a configuration diagram of a power conversion device according to a seventh embodiment of the present invention.
FIG. 17 is a detailed configuration diagram of a fuse blowing determination circuit according to a seventh embodiment of the present invention.
FIG. 18 is a configuration diagram showing a fuse blowing detection circuit of a conventional power converter.
[Explanation of symbols]
1U, 1V, 1W, 1aU, 1aV, 1aW ... three-phase AC power supply 2U, 2V, 2W, 2aU, 2aV, 2aW ... fuse 3, 3a ... three-phase diode converter 4, 4a ... smoothing capacitor 5U, 5V, 5W ... fuse Fusing detection contact 6 Control circuit 7, 7a DC voltage detecting circuit 8 Fuse fusing determining circuit 9 Time setting device 10 Voltage timer output device 11 Detection voltage level setting device 12 Voltage comparison circuit 13 Voltage ripple frequency detection Circuit 14: Detection frequency setting device 15: Frequency comparison circuit 16, 16a DC current detector 17: Current timer output device 18: Detection current level setting device 19, 19a, 19b: Current comparison circuit 20: Current ripple frequency detection circuit 21 ... AC current detector 22 ... OR circuit

Claims (7)

A diode rectifier circuit connected to a three-phase AC power supply via an input fuse,
A smoothing capacitor connected to the DC output of the diode rectifier circuit,
A DC voltage detection circuit that detects a voltage of a DC output unit of the diode rectifier circuit,
Means for determining the operation state of the fuse based on the output of the DC voltage detection circuit,
The power source is characterized in that the operation state of the fuse is determined based on whether or not an output of the DC voltage detection circuit from power-on has reached a predetermined level or more within a predetermined time. Conversion device. A diode rectifier circuit connected to a three-phase AC power supply via an input fuse,
A smoothing capacitor connected to the DC output of the diode rectifier circuit,
A DC voltage detection circuit that detects a voltage of a DC output unit of the diode rectifier circuit,
Means for determining the operation state of the fuse based on the output of the DC voltage detection circuit,
The power converter according to claim 1, wherein the means determines an operation state of the fuse based on whether a ripple frequency included in an output of the DC voltage detection circuit has become equal to or less than a predetermined value. A diode rectifier circuit connected to a three-phase AC power supply via an input fuse,
A smoothing capacitor connected to the DC output of the diode rectifier circuit,
A DC current detector for detecting a current of a DC output unit of the diode rectifier circuit;
Means for determining the operation state of the fuse based on the output of the DC current detector,
The means for judging the operation state of the fuse based on whether or not the output of the DC current detector from the time of power-on has reached a predetermined level or less within a predetermined time. Conversion device. A diode rectifier circuit connected to a three-phase AC power supply via an input fuse,
A smoothing capacitor connected to the DC output of the diode rectifier circuit,
A DC current detector for detecting a current of a DC output unit of the diode rectifier circuit;
Means for determining the operation state of the fuse based on the output of the DC current detector,
The power converter according to claim 1, wherein the means determines an operation state of the fuse based on whether a ripple frequency included in an output of the DC current detector is equal to or less than a predetermined value. A diode rectifier circuit connected to a three-phase AC power supply via an input fuse,
A smoothing capacitor connected to the DC output of the diode rectifier circuit,
An AC current detector for detecting an input current of the diode rectifier circuit;
Means for determining the operating state of the fuse based on the output of the AC current detector,
The power converter according to claim 1, wherein the means determines an operation state of the fuse based on whether an output of the AC current detector is lower than a predetermined level. A plurality of diode rectifier circuits connected to the three-phase AC power supply via input fuses, respectively;
A smoothing capacitor connected to each of the DC output sections of the plurality of diode rectifier circuits;
A DC voltage detection circuit that detects a voltage of each DC output unit of the plurality of diode rectification circuits;
Means for determining the operation state of the fuse based on the output of each of the DC voltage detection circuits,
The power converter according to claim 1, wherein the means determines an operation state of each of the fuses based on whether or not a difference between respective outputs of the DC voltage detection circuit is equal to or more than a predetermined level. A plurality of diode rectifier circuits connected to the three-phase AC power supply via input fuses, respectively;
A smoothing capacitor connected to each of the DC output sections of the plurality of diode rectifier circuits;
A DC current detector for detecting a current of each DC output unit of the plurality of diode rectifier circuits;
Means for determining the operating state of the fuse based on the output of each of the DC current detectors,
The power converter according to claim 1, wherein the means determines an operation state of each of the fuses based on whether a difference between outputs of the respective DC current detectors is equal to or more than a predetermined level.

Images